Apparatus for producing coherent materials



J. A. M DONALD APPARATUS FOR PRODUCING COHERENT MATERIALS 5 Sheets-Sheet 1 'Filed May 16, 1941 Q Ma! ATTORNEY Sept. 28, 1943.

J. A. M DONALD APPARATUS FOR PRODUCING COHERENT MATERIALS Filed May 16, 1941 5 Sheets-Sheet 2 Sept 28, 1943. J. A. MacDONALD 2,330,300

APPARATUS FOR PRODUCING COHERENT MATERIALS F lled May 16, 1941 5 Sheets-Sheet 3 z 5.? v a 603 I l 5 J /1- I 1 ll m 101 a i 25 5 1; 1 Si W ll 94 .45/ 95/ 12 4 I! .98 i I INVENTOR I vanes .19, Macaw/740 BY v . TTORNSY Sept. 28, 1943. J. A. Ma DONALD 2,330,300

APPARATUS FOR PRO DUCING CQHERENT MATERIALS Filed May 16, 1941 5 Sheets-Sheet 4 amen-oz (harness-s02 Call/4% ATTORNEY P 1943- .1. A. M DONALD 2,330,300,

' APPARATUS FOR PRODUCING COHERENT MATERIALS I v Filed May 16, 1941 5 Sheets-Sheet s INVENTOR ATTORNEY dry/v5.5" 0. MM aolwno Patented Sept. 28, 1943 1 APPARATUS FOR PRODUCINGCOHERENT Y MATERIALS James A. MacDonald, Glendale, Califi, assignor to .lohn U. Birnie, LosAngeles, Calif.

Application May 16,1941, SerialNoi393fl9Z (Gig 45),

r1! Claims.

' This invention relates to apparatus for producing materials embodying a mass'of solid or semi-solid particles secured together by binding agents, which can attach the particles to any clesired surface.

' Heretofore, dry or solid particles have been pre-mixed with a suitable liquid binder, this mix ture then being ejected r sprayedon a surface to be treated 'or covered. Such pre-mixing possesses many inherent disadvantages, including the lack of control of the consistency of the dry and liquid mixture being ejected from the spray nozzle, which is caused by variations in the proportions of the respective materials entering the nozzle. This non-uniformity in the'feeding has required constant adjustments of the controls for the binder and dry particles in an at tempt to maintain the uniformity of the sprayed mixture leaving the nozzle. The rapidity with which the proportions varymalies it almost im-' possibleto accomplish effective coordinatedad justments of the control members, with the result that the finished product or material sprayed on the surface to'be treated is improperly and non-uniformly mixed.

It is an object of the invention to overcome the above disadvantages by accurately controlling and gauging the proportionate amountsof the various materials sprayed on the surface to be treated, and in so discharging the particles and binder as to obtain a uniformly mixed coat ing of the sprayed material on the surface to whichit is applied.

Another object of the invention is to provide a spray apparatus capable ofjforming a uniform coating of dry particles and binder on a desired surface by producing an intimate and thorough mixture of such substances after their separate ejection from their respective spray guns or nozzles.

Due to the difficulties attending the premixing of the cork granules andliquid latex, as pointed out above, the present invention contemplates the mixture of the granules and its latex binder primarily at or near the surfaceto which this mass is to be applied. The latex and cork particles are sprayed on the surface in separate, convergent streams which intersect at or near the surface to be treated to effect an intimate and uniform mixing of the latex and .cork'just prior to their deposition on the surface. Because of the ejection of the cork particles and the liquid binder from separate points, their relative proportions may be easily controlled and maintained constant, enabling the production of a uniform productfor-material' possessing many desirable" characteristics, including friction and insulating properties, and also" acoustic qualities. Onaformwhich the invention mayassume is' exemplified in the-following description and il-' lustrated by way of example-in the accompanying drawings, in which: i a

Fig. 1 is a generally side elevat'ional view of the apparatus; i e I Fig. 2 i's'a longitudinai section of the spraying portion of the apparatus;

Fig. 3 is a sectio n taken along the line 3 3 of p gj. 1 l F Fig.4 is asectiontak'en' along the line 44 of Fig. 3; i 1. 1 Fig. 5 is a side elevationof a set of cork and latex guns, and the manner of adjustably supporting them; 1 V a Fig. 6 is a view of a cork gun taken along the lineji6 of Fig. 5;

Fig. 7 is an end view of the cork gun the direction of the arrow! of Fig. 6;

taken in- Fig. 8 is a longitudinal section of the latex gun;

Fig. 9 is a diagrammatic view of the spray patterns formed'by the substances ejected from the cork'and latex spray guns; and

"Fig. 10 is a diagrammatic representation of the flow control systemfor the various spray guns of the apparatus. 1 1

As disclosed 'inthe drawings, the machine or apparatus includes a main supporting frame- 10' having a bed :l l along which aconveyor belt 12 movesfor carrying-the "fabric material l3 with it. .This'belt l2 isdriven at any suitable speed by a driving roll or pulley'i'l l, the slack side of the belt being. supported by the idler pulleysll5 placed at spaced distances along the frame; -i The belt passeslover a'return roller pulley .16, which is rotatably mounted in a movable frame or carriage' I! provided with grooved wheels [8 for riding on tracks H! at the sides of the machine.

A device is provided for holdingthe beltv in proper tension by tending to move thedriv-en pulley carriage ll away from the driving pulley l4.

Theiensioning device consists of 'a cable 20 attached to each side of the carriage lljeach' cable extending generally horizontally from the carriage and passing over anidler pulley 2| suitably supported in bearings near' the lower 'end of a vertical frame 22, from where'the cable 20 extends upwardly in a vertical direction to a 'sec-' on'didler pulley 23" rotatably mounted atthe' upper end of the frame 22. 'The cablepas'ses over anddepen'dsfrom this pulley, and ha's a passes onto the conveyor belt I2 for conveyance;

into a second cabinet 21 where a sealing or fogging coat of latex may be applied, if desired.

From this cabinet, the material proceeds through.

a swing door 28 for passage under a group ofinfra-red lamps 29, which will produce drying, of

the sprayed mixture and vulcanization of the rubber. These lamps 29 are suitably enclosed in a cabinet 33 provided with ventilating slots 3!, through which any vapors released during the vulcanizing process can pass. Following vulcanization, the conveyor belt l2 continuously feeds the material up an inclined ramp 32 for passage between a pair of calender rolls 33, which press the material to reduce its thickness and consolidate the mass to a predetermined extent. After leaving the calender rolls, the coated fabric is conveyed between a pair of final pressure rolls-34, which determine the final thickness of the coated fabric material. The pressure of these rolls 34 may be adjustedto any desired degree. The finished material is then wound up in roll form on a pair of spaced, rotatable idler rolls 35 extending across the frame of the machine.

.jIhe calender rolls 33, pressure rolls 34, idler rolls 35 and driving pulley l4 are rotated-by any suitable driving means (not shown), their periph eral speeds preferably being synchronized. The speed of the driving pulley, and also of the other roller members, can be varied, in order to vary the speed at which the fabric 13 is being conveyed or fed through the apparatus. This speed will be chosen so as to determine the thickness of the coating applied to the fabric and thetime during which the vulcanization or drying-operation takes place under the infra-red lamps. If desired, additional infra-red lamps 36 may be provided along the machine for further heating action upon the material. If a primingcoat of latex is to be provided on the surface of the fabric prior to application of the cork and latex mixture, the, fabric is first caused to enter and proceed through a priming cabinet 31 Where spray guns 38 will eject latex on its surface, this material then passing under infrared lamps: 39 for drying and vulcanization before entering the spraying cabinet or booth where the mixture of cork and latex is applied. The priming coat is preferably only driedssufiiciently to remain'in a slightly tacky state to receive the mixture of cork and latex to better advantage. Any fumes or vapors from the spray booths 25, 3'! will be carried off through the exhaust pipes 40, 4|.

7 The cork particles and liquid latex are caused to mix at or immediately above the surface of the fabric I3 by being ejected from separate guns 42, 43 whose sprays 44, 45 begin to intersect at a point or line 46 which isa certain distance above the fabric, there being substantially complete intersection or coincidence of the sprays at the fabric. These sprays are of generally conical form, diverging from the gun outlets, the latex spray being in atomized formfor complete en-.

veloping of each particle in the cork stream to form a coating therearound which becomes pervious upon drying, due to the evaporation of water and other liquids. As was stated above, the latex provides an elastic binder between each particle, and also between the particles and the fabric material.

The cork particles of the desired mesh are contained in a hopper 4! in which agitator elements 48 are rotatable by a suitable driving device 49 to prevent the particles from coning or packing. The particles pass through a screen 551 in the hopper and into an aggregate chamber 5! into which projects an air nozzle 52 for blowing or forcing thecork through a flexible hose or tubing 53 into the inlet 54 of the cork gun 42. From this inlet 54, the cork particles pass into a nozzle 55 whose front 56 and back 5'! converge in the direction of the nozzle mouth 58, while its sides 59 diverge towards this mouth, which is of restricted shape and of arcuate form, the width of the mouth gradually increasing from its center line to the sides 59, for the purpos of obtaining a uniform discharge of particles and distribution on the fabric surface. This uniformity is assisted by angling the nozzle 55 to-the axis of the inlet 54, causing impingement of the particles on. the back portion 51 as they leave the inlet to be deflected thereby in fan-like fashion across the entire width of the nozzle. The width of the spray leaving the nozzle is also, controlled and made uniform by the arcuate shape 53 at its outlet end.

The sides 59. of the nozzle are split, being formed with overlapping inturned edges 60 to provide for variations in the mouth opening, while preventing leakage or passage of the cork particles through the side faces. This adjustment or variation is accomplished by weldingor otherwise securing bands 6| to the front and back of the nozzle adjacent its mouth 58, and by providing a pair of adjusting screws 62 extending through the bands. The distance between the ends of the front 56 and back 51 of the nozzle is determined by a lock nut 63 threaded on each screw and adapted to engage one of the bands. By loosening the lock nuts and turning each screw 52 to the desired extent, the thickness of the mouth 58 of the nozzle can be alteredto control the amount of material issuing. from the. nozzle and its conical spray pattern.

The latex spray gun 43. (seeFig. 8) is of a known design, being adapted to eject a'generally fiat conical spray. This gun consistsofa body E l-having a fluid inlet fifithrough'which liquid latex may pass, into a discharge passage 65 for ejection through the nozzle 6.7. Such'ejection is determined by a fluid needle 68 adapted; to close the nozzle 6? and extending through the passage 66 and through suitable packings 69 .and packing nuts 78 into a' cylinder ll; whereit is attached to a pistOn'EZ. This. pistoncarries a suitable cup-shaped packing '53 for. slidable engagement with ,the cylindenwall. Air mayenter through an inlet 74 in the body for passageinto the cylinder H, acting on the piston 72 to move it toward the cylinder head 75, andin" so doing causing, the fluid needle 68 to be retracted within the passage to permit: the latex todischarge through the nozzle 67. Such movement of the piston by the action iof'air under pressure: takes place against the force exerted by'a piston spring '16 confined between the piston and cylinder head, this spring returning the needle to closed p osi tion when" the. air pressure is released: The ex-.

tent of opening of. the needle .68 when airunder pressure is admitted to the cylinder is determined enters-the air inlet I8 of the gun body', passing through an air adjustment valve/I9, which'may further control the air pressure and the quantity,

flowing into an air passage 80 exiting into the passage 66 and into an air cap 8| forming an annular chamber with thefiuid nozzle'fil, Air will'pass from this chamber through discharge holes 92 adjacent the fluid nozzle exit, striking the latexejected through this nozzle and atomizing it for intimate mixture with the cork spray from the cork gun 42. The spray pattern can be controlled by means of the spreader adjuster 83 and the retainer nut 84 holdingthe air cap BI in place. H

Both the cork guns 42 and liquid latex guns 4 3 are adjustably mounted to permit alteration in the angles at which they are disposedawith respect to one another and with respect to the fabric material I8, and also the distances, by which they are separated from one another and from the material. In the present instancelsee Fig. 5), the cork gun inlet pipe 54 is mounted in a clamping collar 85 secured to a swivel rod 86 extending from a swivel 8'! adapted to pivot on-a clamping bolt or pin 38 secured to a shaft 89 slidablewithin a clamp 90 adjustably fixed to a supporting rod or bar 9|. It is apparent that loosening of the swivel bolt 98 will permit the angle of discharge of the cork gunto be varied, while loosening of the clamp 90 will permit the swivel shaft 89 to'be adjusted for the purposeofaltering the vertical distance of the cork gun from the fabric. Moreover, the clamp 90 can be shifted onthe supporting bar 9| to alter the distance between the cork and latex guns.

The latex gun 43 is also adjustably mounted in a similar manner by being clampedtoa rod flfi extending from a swivel 81 which can pivot about a suitable clamping bolt or pin 88 fixedto a shaft 99 slidable within a clamp 90 'adjustably mounted on the supporting bar 9|. Due to this arrangement, the latex gun 43 may also pivot about the pin 89 to change its angle of discharge with respect to the material, and this vertical distance thereabove may also be altered by adjusting the shaft 89 in the clamp 90. Similarly, its clamp 99 is shiftable on the supporting bar 9I to alter its distance-from the cork gun 42. r

If the width of the fabric material is substantial, a plurality of sets of cork and latex guns shouldbe employed. Eachset is mountedon a supporting rod or bar 9| extending lengthwise of the machine, the bars being secured to supporting crossmembers 92 attached to sideplates 93, each of which is fixed to a movable side head 9 clamped by bolts 95 to a stationary head 96 forming part of a carriage 91 adapted to be shifted longitudinally within the spray booth 25 on wheels 98 rotatably carried by itsdepending legs 99. By longitudinally shifting the spray carriage 91, all of the guns are correspondingly shifted. Furthermore, by vertically adjusting the movable heads 94 with respect to the stationary heads 96, all of the nozzles will be moved vertically to the same extent.

The simultaneous vertical adjustment of all of the spray guns can be accomplished in any suitable manner. In the present instance (see'Figs. 2; 3 and 4), the fastening bolts 95 extend through verticalguide. slots I00 in the stationary,;,hea d er direction to raise or lower the movable heads by the desired extent, and the bolts ,95' then,

T the stationary head 96.

members, each" of the movable head menibers 94 being shiftable by a chain lfllj hav-' ing' one end attached to the movable head 94, asby means of a bolt I02, the chain passing over a sprocket I03 fastened on an operating'shaft I04 extending across the. machine, and having its other end fastened to the stationary head'96, as by means of a second bolt I05. A hand wheel I06 isfsecured tothe operating shaft I04 externally of the spray booth for the purpose of rotating the shaft and sprockets I03, to elevate or lower the movable head 94 with respect to adjustment is to occur, the fastening bolts 95'are loosened, the hand wheel I96 turned in the proptightened to clampthe movable heads to the stationary heads. It will be noted that the operating shaft I04 extends through a horizontal slot IO'I in the spray booth to permit movement of Vthespray carriage 91 longitudinally of the apparatus.

Fig. ,lO discloses a flow diagram of the system for feeding air, latex, and cork particlesto the various spray guns. Air'is supplied by an air compressor 599, passing therefrom through a suitable line I09 into an air separator H0, where condensate may be eliminated. From this separator, air flows through a line III and through a control valve I I2 into the upper end of a pressuretank H3 containing theliquid latex. This latex is forced under. pressurefrom the tank through a suitable control valve I I4 into a header H5, from where a flexible hose or line .650.

leads to the fluid inlet 65 of each latex spray gun 93.

-Another air line H6 continues from the air separator, branching into a header II! for supplying air to the cylinders H and pistons 12 which control the latex needles 68 in the vari ous spray guns. The passage of air into these cylinders. is determined by a three-way control valve H8 atthe inlet end of the needle header I H, which not only functions to permit or prevent passage of air intothis header and through the flexible hoses II9 connected to the air inlets E4 of the latexguns, but also is capable of adjustment to allow air to bleed back from these guns through their flexible hoses H9 and main header II! to the atmosphere, for the purpose of allowing the'various return springs I6 to move the needles 68 to closed positions. An air line I20 continues from the line IIB to a second air separator I2I, from where the air passes through a pressure regulator I22 into a second air header I23, to which are connectedtherein, for ejection from the air nozzles 52 ex-. tending into the cork particle chambers 5i. The

positions of these nozzles 52 inwardly of the chamber can be varied to alter the quantityof aggregate or particles forced through the flexible tubes 53 and the cork guns 42.

If fogging or sealing latex guns I30 are, em; ployed in the fogging cabinet 21, another header Whenever such vertical" 1:31: may extend from the latex pressure tank; with individual pipes I32 running to each gun I30. Similarly, the regulated, air and needle headers 123', HT may be extended to permit the running r simultaneous spraying or stoppage of liquid latex from the guns.

The cork and latex guns are angled in the direction of travel of the fabric material, the'latex gun 43 of each set being positioned ahead of the cork gun 42. Since the sprays 45, A l from these two guns are to converge, the angle at which the cork gun is adjusted is greater than that of the latex gun, the speed of impact of the cork on the fabric material (3 being determined by the air pressure in the cork nozzle 55. This speed of travel is preferably such as to cause the cork particles toimpinge into the latex stream 45 and prevent the cork from dropping prematurely to any substantial extent before meeting the latex stream. It is preferred that the leading portion 45a of the latex spray impinges on the fabric slightly ahead of the leading portion 44a of the cork spray to provide added adhesion of the cork particles to the fabric and also to insure thorough covering of any cork particles that might be deflected from the main stream or from the surface of the fabric. By causing the streams to intersect, a thorough co-mingling of the cork particles and liquid latex is obtained, to insure the deposition of a uniform mixture on the fabric.

When more than one set of cork and latex guns is employed, they should not only be separated from one another by spaced distances across the width of the fabric, but they should also be staggered, as by arranging-one ahead of another, so that the streams issuing from one set do not interfere with the sprays from any other set, resulting in the deposition of a uniform coating and thickness over the entire surface of the fabric material. Fig. 9 illustrates in a general way the spray patterns from the cork guns G2 and the latex guns 43.

Although particular reference has been made to the discharge of latex from the guns, actually a mixture of latex, curing agents, and accelerating agents are contained in the pressure tank :3 for discharge through the liquid guns 43. The curing agents may be sulphur and zinc oxide, while the accelerators are preferably those which will provide a rapid vulcanization of the latex, since only a comparativel short period of time is available as the material passes under the infra-red lamps 29 in which to effect curing of the latex. Among the accelerators that may be employed are hexamethylenetetramine, butyl zimate, and mercaptobenzothiazole. One particular mixture that may be discharged from the latex guns includes 100 parts by weight of latex, parts of zinc oxide, 1.75 parts sulphur, and 0425 part accelerator. This mixture will be cured in about four minutes at a temperature of 120 degrees centigradesupplied by the infra-red lamps.

-. of proportions of' corkcand latex which might be em ployedrisas follows Cork gran l pounds 50 Latex callous 16 These proportions may be varied, however, without departing from the process, depending upon the characteristics desired in the finished material.

From the foregoing description of the apparatus, it is apparent that a uniform mixture of cork particles and latex can be sprayed on any desired surface, including sheets of fabric material. This material, which may be muslin or burlap, provides a base on which the separate, convergent streams of latex and cork particles are sprayed as the fabric travels continuously in the same direction past the spraying station. By regulating the speed at which the conveyor car-- ries the material past the spraying station, and the quantities of cork particles and liquid latex emanating from their respective nozzles, the thickness and characteristics of the mass deposited on the fabric may be varied to suit different conditions of use. After passing the spraying station, the fabric with the cork granules and latex applied thereto is heated, as by the infra-red-lamps, for the purpose of vulcanizing the latex to effect its permanent adhesion to the cork particles and to the fabric. The fabric with the curedmass thereon is compressed by the calendar andpressure rolls to the required thickness, which can be about i e or greater, depending on the service for which the material is in tended, and the material is then rolled up for storage, shipment or use.

While I have described a preferred form of my apparatus, his to be understood that various changes may bemade therein by those skilled in the art, without departing from the spirit of the invention as defined in the appended claims. The'process and'material described herein are claimed in my application entitled Process for making coherent materials, filed May 16, 1941, Serial No. 393,793.

Having thus described my invention, what I claim and'desire to secure by Letters Patent is:

1. An apparatus of 'the character described, including a conveyor formoving sheet material in agivendirection, a'spray gunfor ejecting one substance toward said material, a second spray gun for ejecting a second substance toward said material; saidguns both'being angled only-in the direction of movement of said conveyor and disposed at anangle to each other so that the streams issuing therefrom intersect and co-mingle toproduce a deposit of a uniform mixture of said substances on-said material.

2. An-apparatus-of the-character described, including a conveyor for movingsheet material in a given direction, a spray gun for ejecting one substance toward-a faceof'said material, a second spray gun for ejecting a second substance toward-the same face of said material, said guns being angledin thedirection of movement of said conveyor and disposed-at an angle toeach other so-that the streams issuing therefrom intersecttabove said material andco-mingle to proin tandem fashion and positioned above the plane of movement of said material for ejecting separate, convergent streams toward a face thereof, one of said guns being adapted to discharge par ticles and the other of said guns being adapted to discharge a binder for securing said particles together, said guns being so disposed with respect to each other as to effect intersection of said separate streams above said material.

4. 'An apparatus of the character described, including a conveyor for feeding sheet material in a given direction, a pair of spray guns arranged in tandem fashion and positioned above the plane of movement ofv said material for ejecting separate, convergent streams toward a face thereof, the trailing gun being adapted to discharge particles and the leading gun being adapted to discharge a binder for securing said particles together, said guns being so disposed with respect to each other as to effect intersection of said separate streams above said material with the discharge from said leading gun striking said material ahead of the stream issuing from said particle gun.

5. An apparatus of the character described, including a conveyor for feeding sheet material in a given direction, sets of spray guns disposed above the plane of movement of said material and across the path of such movement, each set comprising a pair of spray guns arranged in tandem fashion and angled in the direction of movement of said material for ejecting separate convergent streams toward a face of said material, the trailing gun of each set being adapted to discharge particles and the leading gun being adapted to discharge a binder for securing said particles together, said guns being so disposed with respect to each other as to effect intersection of said separate streams above said material, and means for adjust-ably mounting said spray guns to permit the angle between the trailing and leading guns of each Set to be varied.

6. An apparatus of the character described, including a conveyor for feeding sheet material in a iven direction, sets of spray guns disposed above the plane of movement of said material and across the path of such movement, each set comprising a pair of spray guns arranged'in tandem fashion and angled in the direction of movement of said material for ejecting separate convergent streams toward the face of said material, the trailing gun of each set being adapted to discharge particles and the leading gun being adapted to discharge a binder for securing said particles together, said guns being so disposed With respect to each other as to effect intersection of said separate streams above said material, and means for simultaneously adjusting the positions of said guns with respect to said material.

7. An apparatus of the character described, including a spraying station, a conveyor for feedin sheet material through said station in a given direction, a pair of spray guns in said station arranged in tandem fashion and positioned above the plane of movement of said material and angled in the direction of movement of said material for ejecting separate, convergent streams toward a race, thereof, the trailinggun being adapted to discharge a mass of cork granules and the leading gun being adapted to discharge a' la-. tex binder for securing said granules together, said guns being sofdisposed with respect to each other as to effect intersectionofsaid separate streams above said material, and,in'frare d lamps .under'which said conveyor is: adapted to] feed said material after it passes throughsaid spraying station for vulcanizi'ngsaid'latex."

8. An apparatus of the character described, including a spraying station, a conveyor for feeding sheet material through said station in a given direction, a pair of spray guns in said station arranged in tandem fashion and positioned above the plane of movement of said material for ejecting separate, convergent streams toward a face thereof, the trailing gun being adapted to discharge cork granules and the leading gun being adapted to discharge a latex binder for securing said granules together and to said face, said guns being so disposed with respect to each other as to effect intersection of said separate streams above said face, infra-red lamps under which said conveyor is adapted to feed said material after it passes through said spraying station for vulcanizing said latex, and roller means for compacting said mass to a desired thickness.

9. An apparatus of the character described, including a conveyor for feeding sheet material in a given direction, a pair of spray guns arranged in tandem fashion and positioned above the plane of movement of said material and angled in the direction of movement of said material for ejecting separate convergent streams toward a face thereof, the'trailing gun being adapted to discharge cork granules and the leading gun being adapted to discharge a latex binder for securing said granules together and to said face, said guns being so disposed with respect to each other as to effect intersection of said separate streams above said face, means for feeding liquid latex under pressure to said leading gun, means for feeding cork granules to said trailing gun, and control means disposed at a remote point from said guns for determining the discharge of substances therefrom.

10. An apparatus of the character described, including a conveyor for feeding sheet material 'ina given direction, apair of spray guns arranged in tandem fashion and positioned above the plane of movement of said material for ejecting separate convergent streams toward the face thereof,

' the trailing gun bein adapted to discharge cork granules and the leading gun being adapted to discharge a latex binder for securing said granules-together and to' said face, said guns being so to said trailing gun, and control means disposed at a remote point from said leading gun for determining the discharge of latex therefrom.

11. An apparatus of the character described,

including a conveyor for feeding sheet material in a given direction, sets of spray guns disposed above the plane of movement of said material and across the path of such movement, each set comprising a pair of spray guns arranged in tandem fashionfor ejecting separate, convergent streams towardaifacedf said material, the trailing gun of each setbeing adaptedl-toi'discharge corkrgranulesiand theleading gun vbeing. adapted .to discharge. a latex binderffor securing saidgranules together and to said'facegthe guns of each set beingrso disposed with respect to each other as'to efiect' intersection ofsaid separate streamsabove sai'd .face, a 'iatex, pressure feed tank,.means for conveying'latexfromsaidtanklto said leading 10 

